Catalysis of Indium Ion Electroreduction in the Presence of Acetazolamide in Chlorates(VII) Solutions with Varied Water Activity.

The influence of acetazolamide (ACT) on the kinetics and the mechanism of electroreduction of In(III) ions as a function of changes of the water activity was investigated using electrochemical methods (DC, SWV, CV and EIS, CV). The multi-step mechanism of the electroreduction process should take into account the dehydration step of indium ions and the presence of In-ACT (,,cap-pair" effect) active complexes, mediating electron transfer, located in the adsorption layer. Differences in the electrode mechanism in the presence of ACT were observed for higher chlorates(VII) concentrations (above 4 mol ⋅ dm-3 chlorates(VII)) reflected by a lack of step wise nature of the electrode process. The highest catalytic activity was observed in 4 mol ⋅ dm-3 chlorates(VII).

Quantitative Description of Isomorphism in the Series of Simple Compounds.

The introduction of the notion of energy change resulting from the ion exchange in apatites leads to the question: how can some simple isomorphic series be described using the mentioned idea? We concentrated on the simple isomorphic series of compounds: apatite, bioapatite, calcite, aragonite, celestine, K-, Zn- and Cu-Tutton's salts. It was demonstrated in all the series, except Tutton's salts, that the change in energy and the change in the crystal cell volume are, in a simple way, dependent on the change in the ionic radii of the introduced ions. The linear relationships between the variations in energy and in the universal crystallographic dimension d were derived from the earlier equations and proven based on available data. In many cases, except the Tutton's salts, linear dependence was discovered between the change in energy and the sinus of universal angle Θ, corresponding to the change in momentum transfer. In the same cases, linear dependencies were observed between the energy changes and the changes in the volumes of crystallographic cells, and mutually between changes in the crystallographic cell volume V, crystallographic dimension d, and diffraction angle Θ.

Contribution to Knowledge on Bioapatites: Does Mg Level Reflect the Organic Matter and Water Contents of Enamel?

The matter constituting the enamels of four types of organisms was studied. The variability of the ions was presented in molar units. It was proven that the changes in water contents of the enamel are significantly positively related to changes in Mg; inversely, there is also a strong connection with changes in Ca and P, the main components of bioapatite. The variability in the organic matter has the same strong and positive characteristics and is also coupled with changes in Mg contents. Amelogenins in organic matter, which synthesize enamel rods, likely have a role in adjusting the amount of Mg, thus establishing the amount of organic matter and water in the whole enamel; this adjustment occurs through an unknown mechanism. Ca, P, Mg, and Cl ions, as well as organic matter and water, participate in the main circulation cycle of bioapatites. The selection of variations in the composition of bioapatite occurs only along particular trajectories, where the energy of transformation linearly depends on the following factors: changes in the crystallographic d parameter; the increase in the volume, V, of the crystallographic cell; the momentum transfer, which is indirectly expressed by ΔsinΘ value. To our knowledge, these findings are novel in the literature. The obtained results indicate the different chemical and crystallographic affinities of the enamels of selected animals to the human ones. This is essential when animal bioapatites are transformed into dentistic or medical substitutes for the hard tissues. Moreover, the role of Mg is shown to control the amount of water in the apatite and in detecting organic matter in the enamels.

Kinetics and Mechanism of In(III) Ions Electroreduction on Cyclically Renewable Liquid Silver Amalgam Film Electrode: Significance of the Active Complexes of In(III)-Acetazolamide.

The results of kinetic measurements revealed an accelerating effect of acetazolamide (ACT) on the multistep In(III) ions electroreduction in chlorates(VII) on a novel, cyclically renewable liquid silver amalgam film electrode (R-AgLAFE). The kinetic and thermodynamic parameters were determined by applying the DC polarography, square-wave (SWV) and cyclic voltammetry (CV), as well as electrochemical impedance spectroscopy (EIS). It was shown that ACT catalyzed the electrode reaction ("cap-pair" effect) by adsorbing on the surface of the R-AgLAFE electrode. The catalytic activity of ACT was explained as related to its ability to form active In(III)- acetazolamide complexes on the electrode surface, facilitating the electron transfer process. The active complexes constitute a substrate in the electroreduction process and their different structures and properties are responsible for differences in the catalytic activity. The determined values of the activation energy ΔH≠ point to the catalytic activity of ACT in the In(III) ions electroreduction process in chlorates(VII). Analysis of the standard entropy values ΔS0 confirm changes in the dynamics of the electrode process.

Morphometric, Densitometric, and Mechanical Properties of Maxillary Teeth in 5-Month-Old Polish Merino Sheep.

This study was performed to determine morphological, densitometric, mechanical, and elemental characteristics of maxillary teeth in 5-month-old Polish Merino sheep. The total tooth volume (Tvol) was determined using quantitative computed tomography. Micro-computed tomography was used to determine the total enamel volume (Evol), volumetric enamel mineral density, total dentine volume (Dvol), volumetric dentine mineral density, and total tooth enamel and dentine volume (EDvol). Compression testing was used to determine the ultimate force of teeth. Microhardness of enamel and dentine was evaluated using Vicker's test. Elemental analysis of enamel and dentine was performed using a scanning electron microscopy technique. Tooth weight, length, Tvol, Evol, Dvol, and EDvol increased consequently from the lowest values for p2, then for p3 and p4, to the highest values obtained for M1 (all p < 0.05). Ultimate force reached the lowest value for p2 compared with the other teeth (p < 0.05). The comparison of left and right teeth did not reveal significant differences for all the evaluated parameters (p > 0.05). Volumetric mineral density, calcium and phosphorus content, and microhardness were higher in enamel than in dentine, while the opposite results were obtained for magnesium and oxygen (all p < 0.05). Significantly higher enamel microhardness was found in mandibular i1 compared with maxillary and mandibular premolars (p < 0.05). The elaborated experimental model of the determination of maxillary deciduous teeth traits may serve for further studies on the effects of physiological, pathological, environmental, nutritional, pharmacological, and toxicological factors affecting tooth development and mineralized tissue properties.

Interrelationships Between Morphometric, Densitometric, and Mechanical Properties of Teeth in 5-Month-Old Polish Merino Sheep.

Interrelationships between morphological, densitometric, and mechanical properties of deciduous mandibular teeth (incisors, canine, second premolar) were investigated. To perform morphometric, densitometric, and mechanical analyses, teeth were obtained from 5-month-old sheep. Measurements of mean volumetric tooth mineral density and total tooth volume were performed using quantitative computed tomography. Microcomputed tomography was used to measure total enamel volume, volumetric enamel mineral density, total dentin volume, and volumetric dentin mineral density. Maximum elastic strength and ultimate force of teeth were determined using 3-point bending and compression tests. Pearson correlation coefficients were determined between all investigated variables. Mutual dependence was observed between morphological and mechanical properties of the investigated teeth. The highest number of positive correlations of the investigated parameters was stated in first incisor indicating its superior predictive value of tooth quality and masticatory organ function in sheep. Positive correlations of the volumetric dentin mineral density in second premolar with final body weight may indicate predictive value of this parameter in relation with growth rate in sheep. Evaluation of deciduous tooth properties may prove helpful for breeding selection and further reproduction of sheep possessing favorable traits of teeth and better masticatory organ function, leading to improved performance and economic efficiency of the flock.

Morphological, densitometric and mechanical properties of mandible in 5-month-old Polish Merino sheep.

BACKGROUND: Among bones building the axial and appendicular skeleton, the mandible is characterized by unique morphological and functional traits. The aim of the study was to evaluate morphological, densitometric and mechanical properties of mandible in 5-month-old Polish Merino sheep. Using quantitative computed tomography, volumetric bone mineral density (vBMD) and calcium hydroxyapatite density of the cortical bone (CbCa-HA), mean vBMD (MvBMD) and total bone volume were determined. Using computed tomography cross-sectional scans of the mandible, cross-sectional area, second moment of inertia, mean relative wall thickness and cortical index were determined. Three-point bending test was applied to determine mechanical properties. Serum concentration of insulin-like growth factor I (IGF-I) and bone-specific alkaline phosphatase (BAP) was also measured. RESULTS: All the investigated morphometric, densitometric and mechanical parameters of the right and left mandibular halves were not significantly different (P > 0.05). There was no correlation of final body weight, MvBMD, CbCa-HA, BAP and IGF-I with all the analyzed parameters of mandible (P > 0.05). However, positive correlations between the other investigated morphometric, densitometric and mechanical parameter of mandible were found (P < 0.05). CONCLUSIONS: Relationships between morphological, densitometric and mechanical parameters of the mandible indicate that the elaborated experimental model may serve for further studies on metabolic responses of skeletal system to physiological, nutritional, pharmacological, toxicological and environmental factors.

Morphometric, densitometric and mechanical properties of mandibular deciduous teeth in 5-month-old Polish Merino sheep.

BACKGROUND: Caries, enamel hypoplasia, molar incisor hipomineralization, amylogenesis imperfecta, dentine dysplasia, hypophosphatasia and other dental disorders lead to tooth mineralization disturbances and structural abnormalities, decreasing masticatory organ functions. Dental disorders in sheep can lead to premature slaughter before they have attained final stage of their reproductive life and induce economic loss due to high flock replacement costs. Growth rate, health status and meat quality of sheep depends on tooth properties and quality determining in large extent efficiency of the masticatory apparatus and initial food break up. Considering lack of basic anatomical and physiological data on teeth properties in sheep, the aim of the study was to evaluate morphometric, densitometric and mechanical traits of deciduous mandibular incisor, canine and the second premolar obtained at the slaughter age of 5 months of life. RESULTS: The obtained results have shown the highest values of weight, total tooth volume, enamel volume and dentine volume in second premolar. Morphometric and mechanical parameters of incisors reached the highest values in first incisor and decreased gradually in second and third incisor, and in canine. Densitometric measurements have not revealed significant differences of the volumetric tooth mineral density in hard dental tissues between the investigated teeth. CONCLUSIONS: In conclusion, proposed methodological approach is noninvasive since the deciduous teeth undergo physiological replacement with permanent teeth. Deciduous teeth can be easy collected for analyses from large animal population and may reflect mineral status and metabolism resulting from postnatal growth and development of the whole flock. In individual cases, evaluation of properties of deciduous teeth may serve for breeding selection and further reproduction of sheep possessing favorable traits of teeth and better masticatory system functions.

A multi-country test of brief reappraisal interventions on emotions during the COVID-19 pandemic.

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about a situation. Participants from 87 countries and regions (n = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vesus both control conditions) consistently reduced negative emotions and increased positive emotions across different measures. Reconstrual and repurposing interventions had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world. PROTOCOL REGISTRATION: The stage 1 protocol for this Registered Report was accepted in principle on 12 May 2020. The protocol, as accepted by the journal, can be found at https://doi.org/10.6084/m9.figshare.c.4878591.v1.

The dependence of dental caries on oral hygiene habits in preschool children from urban and rural areas in Poland.

INTRODUCTION: Dental caries is considered to be a modern civilization disease;however, the state of oral health negatively influences psychological and sociological relations in children which leads to feelings of discomfort from early age. OBJECTIVE: The aim of study was evaluation of the association between incidence of dental caries (d3ft index) in preschool children from urban and rural areas, and determining the relationship between dental caries intensity and hygienic habits. MATERIALS AND METHOD: 844 children aged 3-6 years from the city and the countryside were examined. The survey was conducted among parents/care givers regarding dental care of children. With parents' consent, the children had a dental examination. RESULTS: The incidence of caries was recorded at the level of 52.61%, with an average value of 4.31 on the d3ft index; however, for the children from the urban area this ratio amounted to 4.15, and in the countryside it reached the value of 4.7. A correlation was found between age and area of residence of the children and various components of hygienic behavior model. CONCLUSIONS: More than a half of the children had dental caries in combination with a high frequency of unsatisfactory hygiene needs. There is a relationship between oral hygiene habits and age of the children, depending on the place of residence.

Negative Effects of Total Gastrectomy on Bone Tissue Metabolism and Volumetric Bone Mineral Density (vBMD) of Lumbar Spine in 1-Year Study in Men.

Gastrectomy induces severe osteoporosis in humans but its quantitative scale within trabecular and cortical compartments was not estimated. The aim of the study was to determine changes of volumetric bone mineral density (vBMD) in lumbar vertebrae (L1-L4) and biochemical bone metabolism markers in serum of patients 1 year after total gastrectomy. The control group consisted of patients (N = 8) subjected to abdominal surgery due to cardiospasmus. Total gastrectomy was performed in the experimental group (N = 6). Volumetric bone mineral density of trabecular and cortical bone of lumbar spine was measured before (baseline) and 1 year after the gastric surgery using the quantitative computed tomography method. Serum concentrations of insulin, insulin-like growth factor-1, tyroxine, interleukin-6, C-terminal telopeptides of type II collagen and bone formation, and resorption markers were determined at baseline and 1 year later, using ELISA, EIA, and IEMA methods. Total gastrectomy induced significant decrease of vBMD values, up to 16.8% and 10.0%, within the trabecular and cortical bone compartments of lumbar spine (P < 0.05). These negative changes of vBMD were associated with significantly increased serum concentration of bone resorption markers such as deoxypyridinoline, pyridinoline, and C-terminal telopeptides of type I collagen, by 13.5%, 32.2%, and 121.5%, respectively (P < 0.05). Neither vBMD nor biochemical bone turnover markers and hormone concentrations were influenced in the control patients. Dramatic bone loss during the first year in gastrectomized patients has proven dynamic osteoporosis progress indicating an importance of treatment interventions in these patients with emphasis on inhibition of intensive bone resorption processes.

Effects of total gastrectomy on plasma silicon and amino acid concentrations in men.

The aim of the study was to determine one-year effects of total gastrectomy on plasma silicon and free amino acid concentrations in patients and evaluate changes of volumetric bone mineral density (vBMD) in lumbar spine. Eight patients were enrolled to the control (CTR) group. Six patients subjected to total gastrectomy (GX group) were included to the experimental group. vBMD in trabecular and cortical bone was measured in lumbar vertebrae at baseline (before surgery) and one year later using quantitative computed tomography. Plasma concentrations of silicon and free amino acids were determined at baseline and one year later using photometric method and ion-exchange chromatography. Body weights within CTR and GX groups were not different after one-year follow-up when compared to the baseline values (P > 0.05). An average annual decrease of vBMD in the trabecular bone in the gastrectomized patients reached 15.0% in lumbar spine and was significantly different in comparison to the percentage changes observed in CTR group (P = 0.02). One-year percentage change of vBMD in the cortical bone in L1 and L2 has shown significantly decreased values by 10.5 and 9.1% in the GX group when compared to the percentage change observed in the controls (P < 0.05). Plasma concentration of adipic acid was significantly higher by 101.6% one year after total gastrectomy procedure in the patients when compared to the baseline value (P = 0.01). Plasma concentration of silicon was significantly lowered by 26.7% one year after the total gastrectomy when compared to the baseline value (P = 0.009). Total gastrectomy in patients has induced severe osteoporotic changes in lumbar spine within one-year period. The observed osteoporotic changes were associated with decreased plasma concentration of silicon indicating importance of exocrine and endocrine functions of stomach for silicon homeostasis maintenance. Gastrectomy-induced bone loss was not related to decreased amino acid concentration in plasma obtained from overnight fasted patients.

Clinical aspect of modern biological restorations: galvano-forming of permanent prosthetic restorations--case report.

Galvano-forming is modern technique used to make esthetic permanent prosthetic restorations displacing lost-wax method. The replacement of wax by metal produces marginal tightness of 70 microm. The technology satisfies esthetic demands, ensures beneficial and long-tern effects. Galvanic products are characterized by high biocompatibility, excellent marginal tightness (tightness of ca 18 microm), pulp protection, chance to apply traditional neutral zinc-phosphate cement and high esthetic quality.

Removable dentures and relations between their construction, adaptation and functionality role and influence on dysgeusia.

A large foreign body inserted into oral cavity, e.g. complete denture, both lower and upper, might cause a temporary or constant dysarthia and dysgeusia. These might be reduced and even completely eliminated by proper dentures construction. Problems with normal articulation might result from construction faults, e.g. too thick denture base, incorrect denture base modelling, wrong teeth placement, lowering or excessive height occlusion. The hypogeusia has been repeatedly observed as the symptom in the course of the complete denture adaptation stage, as well as might keep further. The main role in the mechanism of occurrence of hypogeusia has the limitation of the lingual flexibility, especially of its tip, throughout the use of the complete denture. It provokes difficulties with the accurate course of its physiological activity as well as makes impossible the balancing with the tongue of the cryaesthesia, heath sensibility and tactile sense, which are blocked on the palate.